Is it OK to use topsoil instead of potting soil?

Excuse me, I was wondering if you could help me understand something about gardening. I've been doing some research and I've come across a question that's been puzzling me. Is it actually alright to use topsoil instead of potting soil for my plants? I've heard conflicting opinions and I'm not sure which one to believe. Could you perhaps shed some light on this matter and explain the differences between the two, and why one might be more suitable than the other for certain plants? I would really appreciate your insight on this.